‘HBC 520’ is a product of a controlled breeding program carried out by the inventors in the Yakima Valley of Washington State. ‘HBC 520’ was one of several seedlings resulting from controlled cross made in 2006 with female parent ‘HBC 182’ (unpatented) and male parent ‘986-2’ (unpatented). A single plant of ‘HBC 520’ was selected in 2009, and in 2010 was expanded to 30 plants, which were planted in the area of Toppenish, Wash. The plants were observed and evaluated for several years, and in 2014 a 1 acre test plot of ‘HBC 520’ was established in the area of Moxee, Wash. Throughout several generations of asexual propagation, ‘HBC 520’ has been observed to retain its distinctive characteristics and remain true to type.